Generics and the ArrayList Class - Absolute Java - page 786

PITFALL: An Instantiation of a Generic Class Cannot be
an Array Base Type

Arrays such as the following are illegal (the generic class Pair is the one defined in
Display 14.5 ):

Pair<String>[] a = new Pair<String>[10]; //Illegal

This is a reasonable thing to want to do, but it is not allowed because of technical
details having to do with how Java implements generic classes. The full explanation
for this restriction is beyond the scope of this topic. ■

Display 14.7 Using Our Ordered Pair Class and Automatic Boxing (part 1 of 2)

1 import java.util.Scanner;

2 public class GenericPairDemo2
3 {
4 public static void main(String[] args)
5 {
6 Pair<Integer> secretPair =
7 new Pair<Integer>(42, 24);
8
9 Scanner keyboard = new Scanner(System.in);
10 System.out.println("Enter two numbers:");
11 int n1 = keyboard.nextInt();
12 int n2 = keyboard.nextInt();
13 Pair<Integer> inputPair =
14 new Pair<Integer>(n1, n2);
15 if (inputPair.equals(secretPair))
16 {
17 System.out.println("You guessed the secret numbers");
18 System.out.println("in the correct order!");
19 }
20 else
21 {
22 System.out.println("You guessed incorrectly.");
23 System.out.println("You guessed");
24 System.out.println(inputPair);
25 System.out.println("The secret numbers are");
26 System.out.println(secretPair);
27 }
28 }
29 }

Automatic boxing allows you
to use an int argument for
an Integer parameter.